Semiconductor image sensors are used to sense radiation such as light. Complementary metal-oxide-semiconductor (CMOS) image sensors (CIS) and charge-coupled device (CCD) sensors are used in various applications such as digital still camera or mobile phone camera applications. These devices utilize an array of pixels (which may include photodiodes and transistors) in a substrate to absorb (e.g., sense) radiation that is projected toward the pixels and convert the sensed radiation into electrical signals. An example of an image sensor is a back side illuminated (BSI) image sensor device, which detects light from a backside of a substrate.